Apparatus and systems for processing signals between a tester and a plurality of devices under test

ABSTRACT

Apparatus is for processing signals between a tester and devices under test. In one embodiment, the apparatus includes at least one multichip module. Each multichip module has a plurality of micro-electromechanical switches between a set of connectors to the tester and a set of connectors to devices under test. At least one driver is provided to operate each of the micro-electromechanical switches. Other embodiments are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional application of application Ser. No. 11/410,699,filed Apr. 24, 2006.

BACKGROUND

Others have developed solutions for two touchdown testing of 300 mmwafers containing many NAND dice, e.g. 432 NAND dice having 16 testsites each for a total of 6912 test sites. Generally, this type oftesting utilizes mechanical relays installed in the device under test(DUT) interface of the automatic test equipment (ATE) system. Theserelays are typically located electrically far away from the device undertest (DUT). This distance may create a large impedance mismatch whenreading back from the device. In addition, the maximum data rate fortesting the device may be limited to only 20 MHz.

Mechanical relays are also quite expensive. For example, the typicalmechanical relays may each cost about $8.00. This may limit the returnon investment (ROI) for the customer. Mechanical relays are generallyrated for about 1 to 10 million test cycles. This may create reliabilityissues for the customer over time. Furthermore, mechanical relays areonly rated for operation up to 85° C. This allows testing of NANDdevices using mechanical relays at or below 85° C.

Other solutions for multiplexing a large number of tester pinelectronics (PE) by mounting a plurality of daughter boards on probecards. This will only allow two touchdown testing of 300 mm wafers ofNAND dice. This daughter card approach has limitations with respect totemperature and density. The connector limits the density of switchesthat can be placed on the daughter card and the active silicon switcheshave a temperature limitation of 86° C. when using standard gradeintegrated chips.

SUMMARY OF THE INVENTION

In an embodiment, there is provided apparatus for processing signalsbetween a tester and a plurality of devices under test, the apparatuscomprising at least one multichip module, each of the at least onemultichip module comprising a plurality of micro-electromechanicalswitches between a first set of connectors to the tester and a secondset of connectors to the plurality of devices under test; and at leastone driver to selectively operate each of the plurality ofmicro-electromechanical switches.

In another embodiment, there is provided a system for testing aplurality of devices under test, the system comprising a set of testerelectronics to generate signals for application to the plurality ofdevices under test, and to receive signals generated by the plurality ofdevices under test; a probe card with at least one multichip modulemounted thereon, each of the at least one multichip module comprising aplurality of micro-electromechanical switches between a first set ofconnectors to the set of tester electronics and a second set ofconnectors to the plurality of devices under test, and a driver toselectively operate each of the plurality of micro-electromechanicalswitches; and a probe array to transmit signals between the at least onemultichip module of the probe card and the plurality of devices undertest.

In yet another embodiment, there is provided apparatus for processingsignals between a tester and a plurality of devices under test, theapparatus comprising at least one multichip module mounted directly on aprobe card and operable at a temperature of at least 125° C., and eachof the at least one multichip module having a plurality ofmicro-electromechanical switches between a first set of connectors tothe tester and a second set of connectors to the plurality of devicesunder test.

Other embodiments are also disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative embodiments of the invention are illustrated in thedrawings, in which:

FIGS. 1-3 illustrate one exemplary embodiment of a multichip module forprocessing signals between a tester and a plurality of devices undertest;

FIG. 4 illustrates a system having a probe card with a plurality ofmultichip modules for processing signals between a tester and aplurality of devices under test;

FIGS. 5-7 illustrate another exemplary embodiment of a multichip modulefor processing signals between a tester and a plurality of devices undertest; and

FIG. 8 is a flow chart diagram illustrative of methods of processingsignals between a tester and a plurality of devices under test.

DETAILED DESCRIPTION OF AN EMBODIMENT

Referring to FIGS. 1-7, there is shown apparatus 100 for processingsignals between a tester and a plurality of devices under test. In oneembodiment, apparatus 100 may include various types of multichip modules102, which are also referred to as MCMs 102. FIGS. 1-3 illustrate oneexemplary embodiment of multichip module 102. FIGS. 4-7 illustrateanother exemplary embodiment of multichip module 102.

A top cover 102A of multichip module 102 is shown in FIGS. 1 and 5. Across-sectional plan view 102B of multichip module 102 is shown in FIGS.2 and 6. A bottom portion 102C is shown in FIGS. 3 and 6.

Referring to FIGS. 2 and 5, and each multichip module 102 may include aplurality of micro-electromechanical switches 104, which are alsoreferred to as MEMs 104, between a first set of connectors 106 to thetester and a second set of connectors 108 to the plurality of devicesunder test. Each multichip module may include at least one driver 110 toselectively operate each of the plurality of micro-electromechanicalswitches 104.

Looking at FIG. 4, and in an embodiment, apparatus 100 for processingsignals may include a configuration in which each of multichip modules102 are mounted directly on a probe card 112. Due to the proximity ofmultichip modules 102 to probe card 112 and the devices under test (notshown), one or more of multichip modules 102 may operate at a speed ofat least 100 MHz. In another embodiment, one or more of multichipmodules 102 may operate at a speed above 20 MHz to about 100 MHz.

In an embodiment, one or more of multichip modules 102 may operate at atemperature with a range from about −40° C. to about 125° C. In anotherembodiment, one or more of multichip modules 102 may operate within atemperature range from about 85° C. to about 125° C.

In one embodiment, one or more of multichip modules 102 may be rated forat least 1 billion test cycles. Multichip modules 102 may be rated for10 billion or more test cycles. This is due, at least in part, to themicro-electromechanical switches 104 that may be used instead of othertypes of switches.

Referring to FIGS. 2 and 6, and in an embodiment, the plurality ofmicro-electromechanical switches 104 may be housed in separate MEMs dice114. In one embodiment, each of the separate MEMs dice 114 may includeeight single pole triple throw switches (FIG. 2). In another embodiment,each of the separate MEMs dice 114 may include eight single pole doublethrow switches (FIG. 6).

Looking at FIGS. 1-3 and 5-7, an attachment component 116 may beprovided to secure one or more of multichip modules 102. In anembodiment, attachment component 116 mounts multichip module 102 toprobe card 112 (FIG. 4). Attachment component 116 may includepassageways 118 through multichip module 102 for a set of screws 120 tomount the multchip module to probe card 112 (FIG. 4).

As MEM MCM 102 may be attached to probe card 112 using screws 120 orother fasteners, a new tester does not need to be purchased from asupplier of the ATE system. A customer may simply design a probe careand attach these MEM MCMs to the probe card and install this new probecard assembly onto an existing ATE system.

Generally, MCM 102 may be very thin to allow probe card 112 togetherwith MCMs 102 to fit into an auto loader of a prober. Many screws 120 orother fasteners may be used to attach MCM 102 to probe card 112 toprevent warping.

In an embodiment, one or more of drivers 110 may designed to supply anelectrostatic potential to selectively activate a MEMs gate associatedwith one or more of the plurality of micro-electromechanical switches104. One or more of drivers 110 may be a vacuum-florescent displaydriver die 110. In one embodiment, four drivers 110 (FIG. 2) act as analgorithmic pattern generating system (APGS) and supply theelectrostatic potential to four separate DUTs independently of oneanother. In another embodiment, one driver 110 (FIG. 6) acts as analgorithmic pattern generating system (APGS) and supplies electrostaticpotential to DUTs.

In one embodiment, the second set of connectors of multichip modules 102attach to a probe array 122. This probe array 122 may have at least 6000probe tip needles so as to test at least 6000 test sites of theplurality of devices under test during a single touchdown of probe array122. For example, each multichip module 102 may test 12 DUTs, there maybe 36 multichip modules in attachment to probe card 112 for a total of432 DUTs, and there may be 16 test sites on each one of the DUTs for atotal of 6912 test sites, which in turn requires 6912 probe tip needles.

Referring to FIG. 4, and in an embodiment, there is shown a system 124for testing a plurality of devices under test. System 124 may include aset of tester electronics 126 to generate signals for application to theplurality of devices under test, and to receive signals generated by theplurality of devices under test. System 124 may include probe card 112with at least one multichip module 102 mounted directly on probe card112. Each of the at least one multichip module 102 may include aplurality of micro-electromechanical switches 104 between a first set ofconnectors to the set of tester electronics 126 and a second set ofconnectors to the plurality of devices under test. System may includeone or more drivers 110 to selectively operate each of the plurality ofmicro-electromechanical switches 104. System 124 may further includeprobe array 122 to transmit signals between the multichip modules 102 ofprobe card 112 and the plurality of devices under test.

In one embodiment, probe card 112 may have 36 multichip modules 102mounted thereon. Each of multichip modules 102 may have a plurality ofMEMS dice 114 thereon. Furthermore, each one of the plurality of MEMSdice 114 may each contain a plurality of switches 104. In oneembodiment, switches 104 may include single pole triple throw switches.In another embodiment, switches 104 may include single pole double throwswitches.

Looking at FIG. 1, and in an embodiment, each of multichip modules 102may have 9 MEMS dice 114 thereon. In one embodiment, each of the 9 MEMSdice 114 may have 8 MEMS switches 104. Looking at FIG. 4, and in anotherembodiment, each of multichip modules 102 may have 16 MEMS dice 114thereon. In an embodiment, each of the 16 MEMS dice 114 may have 8MEMSswitches 104.

Referring to FIGS. 3 and 7, and in an embodiment, each one multichipmodule 104 may be housed in a standard package configuration having 780pins which may be configured on bottom portion 102C. A portion of the780 pins form first set of connectors 106, which may provide electricalconnection to tester electronics. Another portion of the 780 pins formsecond set of connectors 108, which may provide electrical connection todevices under test.

Probe card 112 may have a maximum diameter of 440 millimeters. Probecard 112 may form an opening 128 for probe array 122. In an embodiment,opening 128 has a minimum diameter of 330 millimeters. Probe card 112may contains at least 36 of multichip modules 102 mounted thereon.

In an embodiment, probe array 112 may have at least 6000 probe tipneedles so as to test at least 6000 test sites of the plurality ofdevices under test during a single touchdown of probe array 112.

In an embodiment, system 124 enables one touchdown testing of 300 mmwafers containing NAND devices to be tested up to 100 MHz by mountingmicro-electromechanical multichip modules 102 very close to the DUTs.This one touchdown testing cannot be achieved by using mechanical relaysor active silicon devices mounted on daughter boards. Daughter boardsmounted on the probe cannot achieve the required density of switchesbecause of the space required for connectors. Mechanical relays, whichare mounted far from the DUTs, are generally limited to about 20 MHz andcannot achieve a data rate near 100 MHz.

For example, and looking at FIGS. 1-3, to achieve a desired data rate ofabout 20 MHz to about 100 MHz, 72 single-pole, triple-throw (SPTT) MEMswitches 104 and four vacuum-florescent display driver dice (VFD) 110may be integrated into one 780 pin multichip module (MOM) 102. This MOM102 may measure 26 mm×55 mm×34 mm×55 mm (see FIG. 1).

In one embodiment, and looking at FIGS. 5-7, to achieve a desired datarate of about 20 MHz to about 100 MHz, 128 single-pole, double-throw(SPDT) MEM switches 104 and one vacuum-florescent display driver die(VFD) 110 with 32 outputs may be integrated into one 780 pin multichipmodule (MOM) 102. This MOM 102 may measure 26 mm×55 mm×34 mm×55 mm (seeFIG. 5).

MEM MCMs 102 may be fabricated quite inexpensively. For example, an MCMpackage containing 128 SPOT switches with only 780 pins may cost about$300 per package. This drastically improves the return on investment(ROI) for the customer.

As discussed above, mechanical relays are generally rated a maximumtesting temperature of 85° C., which is due to the moving parts insidethe relay housing. Implementations using active silicon devices are alsotypically rated for a maximum testing temperature of 85° C. Using eitherof these, i.e. mechanical relays or daughter boards with active silicon,NAND devices may only be tested up to 85° C. However, using system 100,NAND devices may be tested at temperatures ranging from −40° C. to 125°C. with one or more of MEM MCMs 102.

MEM MCMs 102 are generally mounted very close to the DUTs so as toincrease the maximum data rate for testing NAND devices from 20 MHz to100 MHz, and also to enable testing of the entire 300 mm wafer with onetouchdown.

Utilizing MEM MCMs 102 instead of mechanical relays is also more costeffective and more reliable. A typical mechanical relay is rated for1-10 million cycles. A typical MEM MCM 102 may be rated for 1-10 billioncycles. Using daughter boards limits the density of switches that can bemounted on the probe card due to the space required for connectors.

Multichip modules 102 are generally capable of much higher densitiesthan daughter cards. Mounting multichip modules 102 onto probe card 112enables the customer to double the pin count of the test system whentesting NAND devices without buying a new ATE system.

Using the Agilent V5400 test system, 16 NAND devices with 36 test siteseach may be tested. Each MEMs dice may have 8 SPOT switches. Theelectrostatic potential required to activate the MEMs gate will besupplied by a vacuum-florescent display driver die 110 located insidethe MCM package 102. MCM substrate 102B may be a blind and buried viasubstrate made of NELCO 4000-13 Si, which is a typical MCM substrate.Connectors 106 and connectors 108 may include, but are not limited topins. Such pins of the package may include Be—Cu springs that areattached with silver epoxy to the bottom of the NELCO 4000-13 Sisubstrate. MEMs 104 and single VFD 110 may be located inside MCM 102 andmay be wired bond or soldered to the substrate.

In an embodiment, MCMs 102 may be reusable. MCMs 102 can be transferredform one probe card to another when the probe card becomes damaged or issimply obsolete due to a change in the size or layout on the wafers.

Alignment pins 130 may be provided to align MCM 102 to probe card 112.

Looking now at FIG. 8, and in an embodiment, there is provided a method800 of processing signals between a tester and a plurality of devicesunder test. Method 800 may include connecting 802 the tester and theplurality of devices under test with at least one multichip module, eachof the at least one multichip module having a plurality ofmicro-electromechanical switches between a first set of connectors tothe tester and a second set of connectors to the plurality of devicesunder test. Method 800 may include selectively operating 804 each of theplurality of micro-electromechanical switches.

In one embodiment, method 800 may further include operating 806 the atleast one multichip module at a speed of at least 100 MHz. In anembodiment, method 800 may include operating 808 the multichip module attemperatures from −40° C. to 125° C.

Method 800 may include mounting 810 each of the at least one multichipmodule directly on the probe card.

1. Apparatus for processing signals between a tester and a plurality of devices under test, the apparatus comprising: at least one multichip module, each of the at least one multichip module comprising: a plurality of micro-electromechanical switches between a first set of connectors to the tester and a second set of connectors to the plurality of devices under test; and at least one driver to selectively operate each of the plurality of micro-electromechanical switches.
 2. Apparatus in accordance with claim 1, further comprising a probe card on which each one of the at least one multichip module is directly mounted.
 3. Apparatus in accordance with claim 1, further comprising a plurality of MEMs dice on which the plurality of micro-electromechanical switches are formed.
 4. Apparatus in accordance with claim 1, wherein the separate MEMs dice each include eight single pole triple throw switches.
 5. Apparatus in accordance with claim 1, further comprising an attachment component for each one of the at least one multichip module, and wherein the attachment component mounts the multichip module to a probe card.
 6. Apparatus in accordance with claim 5, wherein the attachment component includes passageways through the multichip module for a set of screws to mount the multchip module to the probe card.
 7. Apparatus in accordance with claim 1, wherein the driver is designed to supply an electrostatic potential to activate a MEMs gate associated with each of the plurality of micro-electromechanical switches.
 8. Apparatus in accordance with claim 1, wherein the at least one driver comprises a vacuum-florescent display driver dice.
 9. A system for processing signals between a tester and a plurality of devices under test, the system comprising: at least one multichip module mounted directly on a probe card and operable at a temperature of at least 125° C., and each of the at least one multichip module having a plurality of micro-electromechanical switches between a first set of connectors to the tester and a second set of connectors to the plurality of devices under test.
 10. A system in accordance with claim 9, wherein the second set of connectors attach to a probe array having at least 6000 probe tip needles so as to test at least 6000 test sites of the plurality of devices under test during a single touchdown of the probe array.
 11. A system for testing a plurality of devices under test, the system comprising: a set of tester electronics to generate signals for application to the plurality of devices under test, and to receive signals generated by the plurality of devices under test; a probe card with at least one multichip module mounted thereon, each of the at least one multichip module comprising a plurality of micro-electromechanical switches between a first set of connectors to the set of tester electronics and a second set of connectors to the plurality of devices under test, and a driver to selectively operate each of the plurality of micro-electromechanical switches; and a probe array to transmit signals between the at least one multichip module of the probe card and the plurality of devices under test.
 12. A system in accordance with claim 11, wherein each of the at least one multichip modules has a plurality of MEMS dice thereon.
 13. A system in accordance with claim 11, wherein each one of the plurality of MEMS dice each contain a plurality of micro-electromechanical switches.
 14. A system in accordance with claim 13, wherein the switches are single pole triple throw switches.
 15. A system in accordance with claim 13, wherein the switches are single pole double throw switches.
 16. A system in accordance with claim 11, wherein the probe card has a maximum diameter of 440 millimeters.
 17. A system in accordance with claim 16, wherein the probe card forms an opening for the probe array, and the opening has a minimum diameter of 330 millimeters.
 18. A system in accordance with claim 11, wherein the probe array has at least 6000 probe tip needles so as to test at least 6000 test sites of the plurality of devices under test during a single touchdown of the probe array. 